A hostile witness, also called an adverse witness, is a person generally called to testify on behalf of either the prosecution or the defense. During the course of the witness examination, the witness may make testimony that weakens the case of the “side” he or she is supposed to be supporting. Alternately, the hostile witness may be testifying against his or her inclination, and is thus antagonistic to the attorney.

In either case, an attorney can ask the judge to declare the witness a hostile witness. If the judge agrees, the attorney then has greater freedom in questioning the hostile witness. He or she can use methods more common to cross-examination in order to attempt to get testimony that is more favorable to his side of the case.

The hostile witness can be more closely examined by the attorney to whom the witness is adverse. The attorney can question the truth of the witness’ statements, the motives of the witness in providing the testimony, and can make direct statements to the witness about what he truly saw or did in regards to the case. The hostile witness can refute such statements with yes or no answers.

The concept of the hostile witness is one greatly romanticized by most crime or legal television shows. Most Law and Order episodes seem incomplete without at least one hostile witness. In real court cases, the hostile witness is much rarer. Generally, attorneys have a fairly good idea of which witnesses are most likely to prove their case. Surprise testimony by a witness who initially seemed supportive to a particular side does occasionally occur, but certainly not with the frequency as is seen in fiction.

However, the hostile witness in fiction adds drama. A sudden change in testimony can certainly change the predictability of “who did it” in dramas. It’s actually quite fun to see a fine actor like Sam Waterston be thrown by the testimony of a hostile witness. The resultant scrambling creates memorable climaxes.

In real applications of the US law, the hostile witness does cause excitement, particularly in high profile cases. Sudden changes in testimony are fodder for news reporters, due to the drama it usually creates.